I've always said the same about the Proglide -- for me it shaves on par with anything else. My Guards have shipped.
Where are you buying your carts for that price? I looked at the prices on Amazon; 100 Bic blades (3 - 5 shaves per blade for me) were about $20; 24 cartridges of the Gillette Fusion Pro-Glide (3 - 5 shaves per cart for me) were about $34.
I have a Feather MR3 handle and FII carts. Good for travel, for variation, and for a smooth and effortless shave. Using that alone would detract some from my enjoyment of this hobby though.